Doxygen

From Wesnoth

Doxygen is a documentation system for C++, C, Java, Python and other language, see http://www.stack.nl/~dimitri/doxygen/index.html.

Wesnoth uses doxygen to generate documentation about its code as html-pages. These are uploaded daily (early in the morning (GMT)) to http://devdocs.wesnoth.org.

Developers can generate these pages locally: in the directory wesnoth/, run the command doxygen Doxyfile

It runs for about 5 minutes, producing about 50 MB of html and graphics. The startpage can then be found at wesnoth/doc/doxygen/html/index.html

To get meaningful documentation, special comments in the code are used, like " /// Calculate X " :

  • In front of some item (class, function, struct, whatever), as in
/// Show titlepage with logo
TITLE_RESULT show_title(game_display& screen, config& tips_of_day, int* ntip);
...
  • just behind some item (variables, enums etc.), as in
enum TITLE_RESULT { TUTORIAL = 0,       ///< Start special campaign 'tutorial'
                    NEW_CAMPAIGN,       ///< Let user select a campaign to play
...

For nice, short examples see titlescreen.hpp and titlescreen.cpp at http://devdocs.wesnoth.org/files.html


Doxygen is quite flexible, and supports a lot of commands to customize and fine-tune the resulting documentation, see http://www.stack.nl/~dimitri/doxygen/commands.html

More details

Doxygen needs some config-files (Doxyfile, doc/doxygen/*.html ...). For wesnoth, these have already been set up.

About every item, doxygen keeps a brief and a detailed description.

  • The brief description should be short, i.e. a single line.

With the option "JAVADOC_AUTOBRIEF", the first sentence of the comment up to the first dot or linebreak is taken as the brief description. Otherwise, a blank line is used to separate brief and detailed description.

  • The detailed description can be as long as you want.

It should be at least 2 lines, so doxygen does not get confused, e.g. thinking it found a second brief description for the same item :-)

  • Doxygen recognizes a lot of special keywords, the most important:
    • @file - description for a file
    • @todo - mark items for a special todo-list
    •  
    • @param - description for parameters for functions etc.
    • @return - general description of a return-value (e.g. "length of string")
    • @retval - description for special return-values (e.g. "-1 : error")

An an example, see fade_logo in titlescreen.cpp

How to document

Doxygen offers quite some options to document items the preferred way in Wesnoth is:
/// to indicate the comment is a Doxygen comment
/** alternatively to start a Doxygen block comment which must end in */
@ to indicate Doxygen keywords

The following sections describe the preferred way to document certain items

functions

In the .hpp there will be a brief 1 line description

In the .cpp there will be a brief description (same as in the header) and a longer description. The following parameters can be used

  • @param - description for a parameter
  • @param[in] - description for a parameter if used as input parameter (only makes sense if @param[out] is also used)
  • @param[out] - description for a parameter if used as output parameter
  • @return - general description of a return-value (e.g. "length of string")
  • @retval - description for special return-values (e.g. "-1 : error")

example .hpp

/// lets you visit a bar
int foo(void* bar, int foobar);

example .cpp

/** lets you visit a bar
 * 
 * foo is an action which lets you visit various bars in the
 * galaxy, which can be rather nice.
 *
 * @param[in] foo  points to the current bar object
 * @param[out] foo points to the new bar object
 * @param foobaar does nothing but was nice to allow a second parameter
 *
 * @return the number of bars visited
 * @retval -1 no bars visited, something bad happened
 * @retval 42 you feel rather enlightened and know the ultimate answer, if you only could remember the question
 */
int foo(void* bar, int foobar)
{
...
}
This page was last modified on 18 August 2010, at 02:07.